National technical standards exist to define the physical and electrical characteristics of electrical plugs and their associated receptacles. The intent of these technical standards is to promote safety and operability between power sources and electronic devices that require electrical power. Historically, a particular electronic device would be designed for a specific source voltage and maximum current source and so would be manufactured with a fixed plug that is configured to insert into its complementary power-source receptacle. For example, an electronic device in North America requiring 220 volts and drawing a maximum current of 20 amperes would be supplied with a plug meeting the National Electrical Manufacturers Association (NEMA) 6-20 standard configured for insertion into a receptacle also conforming to the NEMA 6-20 standard. However, the NEMA 6-20 plug cannot be inserted into a receptacle capable of providing a lower 110 volt source voltage, such as a NEMA 5-15 standard receptacle.
However, electronic devices are currently being manufactured that have built-in power electronics capable of converting various input voltages into an appropriate electrical power for the device. While an electronic device might be configured with a NEMA 6-20 plug, it may be also operable with power provided by a NEMA 5-15 receptacle, even though not physically able to be inserted into the NEMA 5-15 without a plug adapter of some sort.
Plugs may include thermal sensing devices that monitor the temperature of the plug/receptacle junction. The electronic may be programmed to take protective countermeasures, such as reducing power or shutting down if the sensed temperature of the receptacle/plug junction exceeds a temperature threshold. However, the use of an adapter may separate the plug from the receptacle and the thermal sensor in the plug is isolated from the adapter/receptacle junction. The adapter may include a thermal sensor, however the sensor in the adapter may require additional wiring and terminals to interface the sensor to the plug. Therefore, a convenient and cost effective means for measuring the adapter/receptacle junction temperature may still be desired.
It may be possible for users to construct “home built” adapters for connecting a receptacle according to one technical standard to a plug following a different technical standard. However, the “home built” adapters would likely lack any thermal sensing capability. In order to guarantee that thermal sensing of the adapter/receptacle junction is provided, it may be desirable to detect whether an authorized adapter including thermal sensing capability is being used with the plug and operate the electronic device only when an approved adapter is detected.
The subject matter discussed in the background section should not be assumed to be prior art merely as a result of its mention in the background section. Similarly, a problem mentioned in the background section or associated with the subject matter of the background section should not be assumed to have been previously recognized in the prior art. The subject matter in the background section merely represents different approaches, which in and of themselves may also be inventions.